Dulles Corridor Study Vdot Findings 09-16-13

7/27/2019 Dulles Corridor Study Vdot Findings 09-16-13

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Michael W. Garcia, AICP

September 16, 2013

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stations. The Wiehle-Reston East Station is anticipated to open in late 2013 with the other three

stations (Reston Town Center, Herndon, and Innovation Center) planned to open in 2018. The stated

purpose of the study and proposed plan amendments is to make the planned land uses andComprehensive Plan guidance in these areas more consistent with the County TOD policies adopted

in 2007.

The Route 28 Station South Study area focuses on the land area generally bounded by the Dulles

Toll Road to the north, Frying Pan Road to the south, Sully Road (Route 28) to the west and

Centreville Road to the east. The proposed plan amendment for this area focuses higher density

development within walking distance (1/2-mile of the Innovation Center Metro Station and adjusts

the proposed mix of land uses.

The Reston Master Plan Special Study focuses on the land areas surrounding the Wiehle-Reston

East, Reston Town Center, and Herndon Metrorail Stations. The proposed plan amendmentmodifies the proposed lane uses in order to facilitate the evolution of the areas closest to the station

into true mixed-use, walkable, transit-oriented areas.

In addition to the Existing conditions, the Dul les Corri dor Studyconsiders two potential future land

use scenarios. 2030 COG Round 8 represents the current land use densities and types as proposed in

the Fairfax County Comprehensive Plan and adopted by the Metropolitan Washington Council of

Governments (MWCOG or COG); this scenario is considered the baseline future development

against which the proposed plan amendments are evaluated. 2030 Scenario G represents the land use

densities and types recommended by the County for adoption as part of the Dul les Corri dor Study

joint Comprehensive Plan Amendments. Table 1 summarizes the Existing and 2030 land scenarios.

Table 1. Dulles Corridor Study Land Use Comparison

Land Use Existing

(2010 - 2012)

2030 COG Round 8

(Current Comp Plan)

2030 Scenario G

(Proposed Amendments)

Reston Route 28 Total Reston Route 28 Total Reston Route 28 Total

Residential (Units) 5,860 3,309 9,169 16,382 7,002 23,384 24,559 9,289 33,84

Residential (msf) 5.86 3.97 9.83 19.66 8.40 28.06 29.47 11.15 40.

Office (msf) 20.98 4.76 25.74 22.61 5.42 28.03 27.32 8.38 35.7

Retail (msf) 1.09 0.004 1.10 0.99 0.21 1.20 1.63 0.79 2.4

Industrial (msf) 0.84 0.035 0.87 0.70 0 0.70 0.51 0 0.5

Institutional (msf) 2.10 0.15 2.25 1.74 0.28 2.03 2.09 0.15 2.2

Hotel (msf) 0.94 0.86 1.80 1.54 0.69 2.23 3.00 1.18 4.

Total

Development31.81 9.77 41.59 47.26 15.00 62.26 64.03 21.64 85.6

As seen in Table 1, the proposed 2030 Scenario G reflects an increase in the total development

within the Dul les Corri dor Studyarea compared to the 2030 COG Round 8 land use. An additional

10,500 residential units are anticipated as well as approximately 7 million, 1.2 million, and 2 million

additional square feet of office, retail, and hotel space, respectively.


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The report proposes specific Floor Area Ratios (FARs) for areas within each of the Transit Station

Areas. These Floor Area Ratios decrease as distance from the Metrorail Station increases; this

approach would focus the higher density development closest to the Metrorail station, with the goalof encouraging higher levels of transit usage. An example of the proposed development intensities

are provided in Table 2 for the Route 28 Innovation Center Station area.

Table 2. Route 28 Area Planned Land Use Intensity

Distance from Metrorail Range of Intensity (FAR)

Tier 1: Within -mile 2.0 to 3.0 FAR

Tier 2: Between -mile and -mile 1.0 to 2.0 FAR

Beyond -mile 0.75 to 1.5 FAR

Travel demand forecasts for both the 2030 COG Round 8 and 2030 Scenario G land use scenarios

were conducted using Version 2.2 of the MWCOG TPB model (adopted model version when theDul les Corri dor Studywas initiated) and the WMATA Post-Processor Mode Choice Model. The

output from the WMATA Post-Processor model was then fed into the Fairfax County Subarea model

to conduct the assignment step. The study indicates that the total motorized trips (automobile +

transit) within the study area would increase by approximately 37 percent to 519,137 daily trips

under Scenario G compared to the COG Round 8 land use. Internal trips (trips beginning and ending

within the Study Area) would account for 21.5% of the total daily motorized trips for Scenario G,

compared to 15.2% for the COG Round 8 and 10.3% for the 2005 Base Year condition. The 2030

Scenario G land use also is projected to result in a higher transit mode share (9.9%) for home-base

work daily person trips compared to the 2030 COG Round 8 scenario (8.2%); the 2005 Base Year

transit mode share is 2.7% within the Study Area.

A total of 24 existing intersections were included in the operational analysis. Measures of

effectiveness including intersection LOS, seconds of delay, and queue lengths (50th

and 95th

-

percentile) were reported. Results were provided for the following scenarios: 2013 Existing, 2030

COG Round 8 (with Comprehensive Plan improvements but no additional mitigation), and 2030

Scenario G (with Comprehensive Plan improvements and additional mitigation). Table 3

summarizes the number of intersections projected to operate acceptably (LOS A D) or

unacceptably (LOS E or LOS F) during the AM and PM peak periods for each of the land use

scenarios evaluated in the Dul les Corridor Study.

Table 3. Intersection Analysis Summary

Scenario and Peak Period Number of Intersections Operating at:LOS A D LOS E LOS F

Existing (2013)AM 15 3 6

PM 14 3 7

2030 COG Round 8 (No Additional

Mitigation)

AM 9 4 11

PM 9 5 10

2030 Scenario G (With Additional Mitigation)AM 14 4 6

PM 15 3 6


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Additional detail identifying intersections expected to experience degradation in operations and

movements with insufficient storage based on the queuing analysis are summarized in the following

pages.

The following transportation improvements are assumed to mitigate the impact of the proposed land

use changes associated with the Comprehensive Plan Amendments. Improvements not currently

shown on the Countys Transportation map are shown in bold.

1. Route 28widen to 10 lanes with HOV

2. Sunrise Valley Driveextend south of Frying Pan Road

3. Frying Pan Roadwiden to 6 lanes between Route 28 and Centreville Road

4. River Birch Roadextend from Sunrise Valley Drive to Frying Pan Road5. Rock Hill Road Overpass add 4 lane bridge from Innovation Avenue to Sunrise Valley

Drive/Sayward Boulevard6. Fairfax County Parkwaywiden to 6 lanes with HOV

7. Fairfax County Parkway/Sunrise Valley Drivegrade separate8. Fox Mill Roadwiden to 4 lanes from Reston Parkway to Monroe Street

9. West Ox Roadwiden to 4 lanes from Lawyers Road to Centreville Road

10. Monroe Streetwiden to 4 lanes from West Ox Road to Herndon

11. Town Center Parkway Underpass

12. Pinecrest Roadextend from South Lakes Drive to Sunrise Valley Drive

13. Reston Parkway widen to 6 lanes from South Lakes Drive to Baron Cameron

Avenue

14. Soapstone Overpass add overpass over Dulles Toll Road from Sunset Hills Road to

Sunrise Valley Drive at Soapstone Drive15. South Lakes Overpass add overpass over Dulles Toll Road from Sunset Hills Road

to Sunrise Valley Drive at South lakes Drive

16. Reston and Route 28New grid of streets

17. Intersection improvements at 15 of 24 intersections evaluated in Study

The analysis presented in the report for Scenario G also assumes several intersection improvements

which have been suggested by MWAA at the ramp terminal intersections of the Dulles Toll Road.

These improvements have not been formally adopted in a plan by MWAA and may be subject to

change.

The following transit service improvements are also proposed to serve the study area under the 2030

Scenario G land use:

1. Improve service frequencies to match Fairfax County Transit Development Plan

2. Bus Rapid Transit (BRT) along Centreville Road from I-66 to the Innovation Center

Metrorail Station and into Loudoun County (10-minute headways)


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3. Express Bus on Route 28 from I-66 to Route 7 in Loudoun County with 30 minute

frequencies4. Express Bus on Fairfax County Parkway from the Fairfax Center area to the Herndon

Metrorail Station with 30 minute frequencies.

VDOT findings and comments

The following detailed comments regarding both studies submitted are compiled together below.

Those that specifically reference one document are noted as either the Transportation Studyor

Corridor Study. The comments have been grouped into three categories: cumulative impacts,

clarifications, deficiencies and suggestions.

Cumulative Impacts

1. Does the modeling reflect the trip generation from the proposed densification of Tysons Corner

as well as the additional developments in Loudoun County (Dulles World Center) near the Route

28 station area? What REGIONAL background development is included? Per the Tysons Corner

Studies, the Dulles Toll Road is over capacity. However, based on the freeway link model results

contained in Tables 2.5 and 2.6 of Appendix 2 of the Transportation Study, none of the freeway

links on Route 28 or the Dulles Toll Road are expected to operate beyond their capacity (v/c >1.0) in the morning or afternoon peak hour with the future land use proposed by the plan

amendment (Scenario G). This inconsistency with other studies indicates that not all regional

development is considered within the travel demand model and that this study may not accurately

represent the impact on these roads.

2. It appears that only a relatively small area was considered in the study. What is the downstream

impact?

3. It should be noted that the queuing and level of service results may be worse than indicated in the

studies due to the failing intersections and over-capacity links. SimTraffic may reveal gridlock

throughout the network.

Clarifications

Land Use Assumptions and Travel Demand Model Methodology

4. Please provide narrative and explain how the job-to-household data on page 10 of the

Transportation Studywas obtained. It should be noted that the while the 4:1 ratio is still not

satisfactory, it shows significant improvement over the existing scenario which is commendable.


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5. To estimate the residential square footage, factors of 1000 and 1200 sf per dwelling unit were

assumed for existing and 2030 scenarios, respectively (see pages 5 and 6 of the Corri dor Study).Please explain the inconsistency. These values may be applicable to multifamily dwelling units

and are not suitable for town homes. Please explain.

6. As mentioned on page 17 of the Transportation Study, why was a 2005 model run used for

model validation instead of a more recent year, and what year of traffic counts were used?

Traffic Volumes

7. 2010 traffic counts increased by a growth rate of 1% per year were used at 21 of the intersections

analyzed to bring them to 2013. Please provide an explanation for this growth rate.

8. Some of the 2030 volumes, more than expected, shown in Figures 4.9A-C of the

Transportation Studydecrease when compared to existing volumes. Please revisit / explain.

Improvements/Mitigation

9. Per the study, Wiehle Station is expected to open at the end of this year. The desired land use

changes that this Comprehensive Plan Amendment hopes to affect will not occur for some time.

As a result the demand on the roadway network will be greater initially while higher density

mixed-use development is being established. How will this be addressed and will the

transportation network suffer in the short term?

10.A change from the current Level of Service standard of D to E is proposed within mile of the

planned rail stations (TOD areas). It appears that this standard will apply to the following 10

intersections. Three of these intersections do not meet this standard with the proposed mitigation

measures. Knowingly establishing an unattainable standard does not address future traffic

congestion. Please explain.a. Fairfax County Parkway and Sunrise Valley Drive

b. Reston Parkway and Sunrise Valley Drive

c. Reston Parkway and Dulles Toll Road eastbound ramps

d. Reston Parkway and Dulles Toll Road westbound ramps

e. Reston Parkway and Sunset Hills Road

f. Reston Parkway and Bluemont Way

g. Wiehle Avenue and Sunrise Valley Drive

h. Wiehle Avenue and Dulles Toll Road eastbound ramps

i. Wiehle Avenue and Dulles Toll Road westbound ramps

j. Wiehle Avenue and Sunset Hills Road.

11. The Tiered Approach on page 20 of the Transportation Study indicates that signaloptimization would be the first step for mitigation, but for 2030 Scenario G, it appears that

geometric improvements were considered before signal optimization. Please explain.

12. For Full Mitigation of Scenario G on page 67 of the Transportation Study, signal

adjustments were considered as an improvement. Please explain what FCDOT considers signal

adjustments in addition to optimization (Signal optimization has already been considered as an

improvement).


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Trip Reductions

13. The trip reduction assumptions within the TOD districts seem to be generally consistent withprofessional studies of TOD trip generation. What assumptions were used regarding trip

reduction in the non-TOD portions of the study area? Research suggests that the extent of

reduction in trip making declines with distance from transit stops and distance from the central

business district.

14. Trip reduction goals for the project are shown on page 20 of the Corri dor Study. What are the

final trip reduction percentages? Please provide a table showing how much each factor (TDM,

TDP, TOD, internal capture, pass-by) contributes to trip reductions.

15.The trip reduction goals shown in Table 5 on page 20 of the Corri dor Studyare lower than those

used in the Tysons Corner studies. Concerns remain as to whether these are achievable. Please

explain.16.It is unclear how the anticipated transit ridership numbers reported throughout the

Transportation Studyrelate to one another, how accurate they are and whether the metro will be

able to accommodate the anticipated riders. Tables 4.1 4.5 report various types of trips and

their anticipated quantity, Tables 4.6 and 4.7 report percentages of types of trips, Table 4.8

reports total transit trips and Table 4.12 reports transit shares by station. However, none of these

numbers or percentages clearly correlates to one another. Furthermore, the text on page 70

indicates that 4300 passengers is the maximum load for the six-hour peak period, however, when

compared to the total Transit Trips in Table 4.8 of 13,879, this is only 31 percent of the total.

Please clarify.

Synchro Inputs

17. Please check the Synchro files and make sure that the signal phasing for all intersections is

correct. For example, the signal phasing for Sunrise Valley Drive/Reston Parkway (#7) does not

appear to be correct for all scenarios. The Sunrise Valley Drive approaches should be split

phased.

18. At Sunrise Valley Drive/Frying Pan Road (#1), the NB/SB through volume is low (less than

100 vph) for the future 2030 scenarios. Are two through lanes needed?

19. The Synchro files for 2030 Scenario G show four receiving lanes on NB Centreville Road at

Sunrise Valley Drive, and then the 4th lane is dropped. What is the 4th lane for?

20. Compared to the 2030 COG Round 8 scenario, the AM and PM intersection entering

volumes for 2030 Scenario G do not change consistently. For example, for the following

intersections the AM volume decreased, but PM volumes increased: Sunrise Valley Drive/Frying

Pan Road (#1), Wiehle Avenue/DTRWB ramps (#19) and Hunter Mill Road/Sunrise Valley

Road (#21).

21. Please check all volume inputs in the Synchro files. For example, for Scenario G in the PM

peak hour at Centreville Road/Dulles Toll Road WB ramps the SB volumes are shown as 0.


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Synchro Results

22. On page 22 of the Transportation Study it is stated that Synchro results were averagedWhat was averaged? Synchro does provide MOEs per lane group, approach, and the whole

intersection. Please explain the methodology on how the average was derived, and its relevance.

23. Compared to 2013 existing conditions, some intersections (#8, #12, #13 and #23) for 2030

COG Round 8 scenario have increased volumes but decreased delays with the same lane

configurations. Please explain.

24. A comparison between 2030 COG Round 8 and Scenario G results should be provided in

order to support the statement that Scenario G performs better than the COG Round 8 scenarios

on the transportation network (included in 4.6 Summary and Next Steps).

25.A number of signalized intersections within the study area were included in the Synchro analysis

but are not included in the summary tables and figures. It appears that the decision to excludethese intersections was based on an urban local functional classification. Please clarify why these

intersections are not included within the text, tables and figures of the study.

Measures of Effectiveness

26.How would levels of service on the toll road and toll road ramps be impacted under COG

Round 8 and Scenario G?

Deficiencies

Trip Reduction

27.Table 5 of the Corri dor Studycontains the trip reduction goals for the study area. Does FairfaxCounty have a plan in place to reach these goals? If so, please provide a reference to the

appropriate plan in the report and discuss how progress towards these goals will be monitored. A

menu of specific Travel Demand Management measures that are envisioned to reach these trip

reduction goals should be included in the Comprehensive Plan.

28.Considering the proposed land uses (specifically the 1,632,657 sf retail) shown in Table 1 of the

Corri dor Studyand the location of the Rt 28 Station Area within a suburban setting with limited

retail opportunities, VDOT is concerned that the actual mode split estimation may be optimistic.

A concern remains that the external trip count into this area may be much higher, and those trips

will be via automobile.

Synchro Analysis

29.The entire study area should be modeled as one single network. It is currently shown as five

separate arterials without the Dulles Toll Road. It is imperative that the Dulles Toll Road (DTR)

is included in all modeling as a single integrated simulation system. As mentioned in comment

1, the cumulative impact of other development and travel in the area adjacent to those considered

in this Comprehensive Plan Amendment must be included to accurately understand travel in the

study area.


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30.Furthermore, and in accordance with the recently adopted VDOTs Traffic Operations Analysis

Tool Guidebook (TOATG), Synchro is not the preferred tool for analysis of integrated networks.Use of VISSIM or CORSIM is currently required.

31.All components of the freeway system (basic freeway segment, weave and merge / diverge)

should be analyzed along with the connecting roadways so that the operational functionality of

DTR vis--vis street network is known. The operation of the surface street network, as it is

currently shown, without the DTR is inadequate in predicting the future traffic conditions in this

area.

32.The Synchro printouts in Attachment 4 of the Transportation Studydo not match many of the

tables and figures within the report for Scenario G. Observations and conclusions reported in

this memo reflect the information from the Synchro printouts where there is a discrepancy.

Please verify all volume inputs in Synchro. For example, Scenario G, PM Peak, the southbound

Centreville Road approach at the Dulles Toll Road westbound ramps is entered as 0 vehicles inSynchro, but should be 1,664 vehicles.

33.Traffic counts for the 24 study intersections were not provided; therefore, none of the data used

in Synchro based on the counts can be confirmed. Were the volumes independently verified by

the analyst?

34.Default values were used for a number of data entries including: lane widths (12 feet), grades

(0%) and heavy vehicle percentages (2%). Please confirm that these values are appropriate for

the Study Area.

35.Peak hour factors of 1.0 were used for nearly all analyses. Please justify the use of 1.0 or modify

the analyses appropriately.

36.Minimum green times are insufficient to accommodate pedestrians wishing to cross. Pedestrian

phasing / timings must be included in all 2030 Synchro models at all pertinent intersections. Thischange will significantly affect the levels of serve at a number of intersections.

37.Bus blockages were entered for the intersection of Centreville Road and Sunset Valley Road but

no other intersections. A consistent approach to the use of the bus blockage input should be

applied.

38.Please check all the Synchro files and ensure that they are free of errors, particularly fatal errors

which prevent the user from running SimTraffic simulations. Several issues were noted with

inconsistencies with input lanes and receiving lanes.












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41.For existing conditions, the intersections of Sunrise Valley Drive/Frying Pan Road, Frying Pan

Road/Centreville Road and Centreville Road/Coppermine Road are included in the Rt. 50

Synchro files but not included in the Dulles corridor Synchro files. It appears that the coordinatedcycle length for the intersections of Centreville Road are different in these two files. Please

include all intersections analyzed in this study in one file for each peak hour. This also applies to

the 2030 COG Round 8 scenario. Cycle lengths should be consistent.

42. In the Synchro files, please check lane configurations thoroughly and code turn bays at

intersections appropriately to make the number of lanes on roadway segments reasonable. For

example, 1. For Scenario G, no turn bays are coded for the WB approach at Frying Pan

Road/Sunrise Valley Drive and the WB segment is shown as 6 lanes which doesnt seem

reasonable; 2. Centreville Road between the ramp intersections at Dulles Toll Road has one NB

lane and three SB lanes.

43. Some of the proposed cycle lengths are 126 and 162 seconds. Please use cycle lengths that

are multiples of 10 or 5.44. Clustered Intersections with a single controller such as Sunset Hills Road/Hunter Mill Road

(#24), and Dulles Toll Road WB On-Ramp/Hunter Mill Road (#23) should be analyzed as such

in all 2030 scenarios.

Improvements/Mitigation

45.Please address the potential impacts of the suggested MWAA ramp terminal intersection

improvements not being implemented. How likely are these improvements? How would

alternate mitigation measures be developed to help mitigate the additional impacts?

46.Both studies propose to accept LOS F for some intersections based on the rationale of providing

a transportation system which is balanced and supportive of transit, pedestrians and bicycles.This is an important principle, but the huge scope and long development time-frame of the

planned development justify planning for full mitigation of Scenario G. It is not clear how the

road improvements would preclude a bike and pedestrian friendly environment. Full mitigation

to LOS E should be included in the Comp Plan. If a decision is made to ignore the possible

future need for right of way reservation for some of the improvements, it may be difficult to

reverse that decision in the future if the need for additional right of way becomes apparent.

Tables and Figures

47.As previously mentioned, the Synchro printouts in Attachment 4 do not match many of the tables

and figures within the report for Scenario G. Please update the appropriate figures and tables orSynchro analysis, depending on which item is correct.

48.Tables 2.4 and 2.5 of the Transportation Studyare the same. Table 2.4 should show the net

change in land use from Existing to Scenario G.

49.In Figure 4.9B at Intersection 9 of the Transportation Study, the westbound right turn lane

should not be shown as proposed as it is also shown as existing on Figure 4.2B.

50.Figure 4.9A of the Transportation Studyshows two SB thru lanes for Rt 28 and 62 VPH in the

a.m. and p.m. peak hour respectively. Please provide a better lane utilization to assist with the

more than 3000 VPH right turn volume.


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51.In Table 4 of the Corri dor StudyMcNair Farms Drive should be replaced with a different

example as it is not in Land Unit A.

Measures of Effectiveness

52.While the County finds that the transportation network will generally perform to higher levels of

service at most intersections under Scenario G with optimization, the report points out that one

congestion metric, vehicle hours of congestion, will increase slightly. Even if the inconvenience

to automobile travelers is accepted as part of the price of creating more walkable transit-

supportive communities, however, there could be significant concerns arising from the fact that

emergency vehicles and rubber-tired transit or paratransit vehicles could be hampered by

gridlock. The County should consider the ability to effectively serve these areas with EMS and

transit.

53.The overall intersection level of service for the proposed land use scenario (Scenario G) after

optimization and mitigation, is below the proposed standard (E for TOD, D others) at thefollowing intersections (overall delay is also indicated). Each of these locations is listed in Table

4.18 as needing further improvements that are not recommended. Left unaddressed the delay

experienced at the intersections will impact not just the intersections, but the roadway links and

ripple through the roadway network, creating gridlock. How will the deficiencies be addressed at

these intersections?

a. Sunrise Valley Drive and Frying Pan RoadPM (174.4)

b. Centreville Road and Sunrise Valley DrivePM (81.0)

c. Centreville Road and Dulles Toll Road EB rampsAM (89.0)

d. Reston Parkway and Sunset Hills RoadAM (150.6), PM (217.7)

e. Reston Parkway and New Dominion ParkwayPM (86.0)

f. Wiehle Avenue and Sunrise Valley DriveAM (147.7)g. Wiehle Avenue and Sunset Hills RoadAM (146.3), PM (272.2)

h. Hunter Mill Road and Sunrise Valley RoadAM (258.0), PM (149.8)

i. Hunter Mill Road and Dulles Toll Road WB rampsAM (67.8), PM (108.7)

j. Hunter Mill Road and Sunset Hills RoadAM (63.6), PM (65.5)

54.Comparison of the COG Round 8 and Scenario G Synchro analyses, indicates that the overall

intersection level of service degrades at the following intersections. It should be noted that the

COG Round 8 analysis results do not include mitigation measures and the Scenario G results do.

Comparing COG Round 8 without mitigation measures to Scenario G with mitigation measures

is misleading because the levels of service reported for COG Round 8 appear worse than they

would be with mitigation measures and downplays the level of degradation in delay and level of

service expected when considering the Scenario G land use.Table 4. Comparison of COG Round 8 and Scenario G AM Peak Hour LOS and Delay

Intersection AM Peak #COG Round 8 Scenario G

Delay LOS Delay LOS

Centreville Rd/Dulles Toll Rd EB Ramps 5 42.5 D 89.0 F

Fairfax County Pkwy/Spring St 10 53.3 D 65.2 E

Reston Pkwy/Sunset Hills Rd 14 148.8 F 150.6 F

Wiehle Ave/Sunrise Valley Dr 17 87.4 F 147.7 F

Wiehle Ave/Sunset Hills Rd 20 79.8 E 146.3 F

Hunter Mill Rd/Sunrise Valley Dr 21 77.0 E 258 F

Hunter Mill Rd/Dulles Toll Rd WB Ramps 23 31.3 C 67.8 E


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Table 5. Comparison of COG Round 8 and Scenario G PM Peak Hour LOS and Delay

Intersection

PM Peak #COG Round 8 Scenario G

Delay LOS Delay LOS

Centreville Rd/Dulles Toll Rd EB Ramps 5 26.4 C 39.2 D

Reston Pkwy/Dulles Toll Rd EB Ramps 12 13.6 B 33.8 C

Reston Pkwy/Sunset Hills Rd 14 211.6 F 217.7 F

Reston Pkwy/New Dominion Pkwy 16 73.2 E 86.0 F

Wiehle Ave/Sunset Hills Rd 20 183.5 F 272.2 F

Hunter Mill Rd/Sunrise Valley Dr 21 56 E 149.8 F

Hunter Mill Rd/Dulles Toll Rd WB Ramps 23 68.4 E 108.7 F

Hunter Mill Rd/Sunset Hills Rd 24 48.2 D 65.5 E

55.Based on the non-freeway link results contained in Appendix 2 of the Transportation Study,there are several roadway links within the study area that are expected to operate beyond their

capacity with the proposed plan amendment (Scenario G). The v/c ratios at these locations are

also greater than those for the currently adopted future land use conditions (COG Round 8) for

nearly all locations.

Table 6. Comparison of COG Round 8 and Scenario G Non-Freeway Link Analysis Results

Location ID

and

Direction

Roadway Period

COG Round 8

v/c

Scenario G

v/c

1 EB Frying Pan Road AM 1.01 1.08

1 WB Frying Pan Road PM 1.11 1.322 SB Sunrise Valley Road PM 1.14 1.53

6 EB Sunrise Valley Road PM 1.30 1.87

9 EB Sunrise Valley Road PM 0.89 1.03

14 SB Fairfax County Parkway AM 1.07 1.19

17 EB Sunrise Valley Road AM 1.15 1.29

20 NB Reston Parkway AM 1.24 1.24

20 SB Reston Parkway PM 1.13 1.49

23 EB Sunrise Valley Road AM 0.88 1.08

24 WB Sunrise Valley Road AM 1.00 1.10

26 EB Sunset Hills Road AM 0.73 1.46

26 EB Sunset Hills Road PM 0.80 1.6428 EB Sunset Hills Road AM 0.91 1.30

28 WB Sunset Hills Road PM 1.43 1.05

31 NB Hunter Mill Road AM 1.16 1.12

56.Based on the queuing analysis reported in Attachment 4 of the Transportation Study, the 50th

percentile queues are expected to extend beyond the storage provided or into the adjacent study

intersection at the locations listed below. (Not all storage lane lengths were included for the

intersection of Sunrise Valley Drive and Frying Pan Road.)


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a. Morning Peak

i. Centreville Road and Coppermine Roadeastbound left turnii. Centreville Road and Sunrise Valley Roadwestbound right and southbound left turns

iii. Fairfax County Parkway and Dulles Toll Road EB rampseastbound left turn

iv. Fairfax County Parkway and Spring Streetnorthbound left turn

v. Reston Parkway and Sunrise Valley Roadeastbound through

vi. Reston Parkway and Dulles Toll Road WB ramps westbound right turn and

northbound through

vii. Reston Parkway and Sunset Hills Road eastbound through, northbound left and right

turns

viii. Reston Parkway and New Dominion Parkway northbound and southbound left turns

and southbound through

ix. Wiehle Avenue and Sunrise Valley Driveeastbound left turnx. Wiehle Avenue and Sunset Hills Road eastbound right, northbound left and

southbound left turns

xi. Hunter Mill Road and Sunrise Valley Drive eastbound and northbound left turns and

northbound through

b. Afternoon Peak

i. Sunrise Valley Drive and Frying Pan Roadeastbound through

ii. Centreville Road and Frying Pan Roadeastbound right turn

iii. Centreville Road and Coppermine Roadeastbound left turn

iv. Centreville Road and Sunrise Valley Road eastbound left, westbound left, westbound

right, northbound right and southbound left turnsv. Centreville Road and Dulles Toll Road EB ramps eastbound left turn, northbound

right turn and southbound through

vi. Fairfax County Parkway and Sunrise Valley Roadeastbound and westbound left turns

vii. Fairfax County Parkway and Dulles Toll Road EB rampseastbound left turns

viii. Fairfax County Parkway and Dulles Toll Road WB rampswestbound left turn

ix. Reston Parkway and Sunrise Valley Roadwestbound left turn, westbound through and

westbound right turn

x. Reston Parkway and Dulles Toll Road WB ramps westbound right turn and

southbound through

xi. Reston Parkway and Sunset Hills Road eastbound right turn, westbound left turn,

northbound through and southbound through

xii. Reston Parkway and Bluemont Waysouthbound through

xiii. Reston Parkway and New Dominion Parkway eastbound left, eastbound right,

westbound left and southbound left turns and northbound and southbound throughs

xiv. Wiehle Avenue and Sunrise Valley Roadeastbound left and westbound right turns

xv. Wiehle Avenue and Dulles Toll Road WB rampssouthbound through

xvi. Wiehle Avenue and Sunset Hills Roadeastbound left, eastbound right, northbound left

turns and northbound through


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xvii. Hunter Mill Road and Sunrise Valley Road northbound left turn and northbound

throughxviii. Hunter Mill Road and Dulles Toll Road EB rampseastbound right

57.Based on the queuing analysis reported in Attachment 4 of the Transportation Study, the 95th

percentile queues are expected to extend beyond the storage provided, or into the adjacent study

intersection, at the locations indicated in the previous comment and at the additional locations

listed below.

a. Morning Peak

i. Sunrise Valley Drive and Frying Pan Roadeastbound through

ii. Centreville Road and Frying Pan Roadnorthbound left turn

iii. Centreville Road and Sunrise Valley Roadwestbound left turn

iv. Centreville Road and Dulles Toll Road EB ramps eastbound left turn and southboundthrough

v. Fairfax County Parkway and Dulles Toll Road EB rampseastbound right turn

vi. Fairfax County Parkway and Spring Streeteastbound left turn and southbound through

vii. Reston Parkway and Sunrise Valley Road eastbound left, westbound left, westbound

right and northbound right turns

viii. Reston Parkway and Dulles Toll Road EB rampseastbound right turn

ix. Reston Parkway and Sunset Hills Roadwestbound left, southbound left turns

x. Reston Parkway and New Dominion Parkway eastbound right, westbound left,

westbound through

xi. Wiehle Avenue and Sunrise Valley Drivesouthbound left turn

xii. Hunter Mill Road and Dulles Toll Road EB ramps eastbound right turn andsouthbound left turns

xiii. Hunter Mill Road and Sunset Hills Roadeastbound left and northbound left turns

b. Afternoon Peak

i. Centreville Road and Frying Pan Roadwestbound left turn

ii. Fairfax County Parkway and Sunrise Valley Roadwestbound right turn

iii. Fairfax County Parkway and Spring Streeteastbound left and southbound through

iv. Reston Parkway and Sunrise Valley Roadeastbound left turn

v. Reston Parkway and Dulles Toll Road EB rampseastbound left turn

vi. Reston Parkway and Dulles Toll Road WB rampswestbound right turn

vii. Reston Parkway and Sunset Hills Road westbound right, northbound left and

southbound left turns

viii. Reston Parkway and Bluemont Wayeastbound left turn

ix. Reston Parkway and New Dominion Parkway westbound right and northbound left

turns

x. Wiehle Avenue and Sunrise Valley Roadsouthbound left turn

xi. Wiehle Avenue and Dulles Toll Road WB ramps westbound left and right turns,

westbound through


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xii. Wiehle Avenue and Sunset Hills Roadwestbound left turn

xiii. Hunter Mill Road and Sunrise Valley Roadeastbound and southbound left turnsxiv. Hunter Mill Road and Dulles Toll Road WB ramps westbound left turn, northbound

left turn and southbound through

xv. Hunter Mill Road and Sunset Hills Roadeastbound left turn and northbound through

Suggestions

55. The study includes an extensive list of geometric improvements and travel demand reduction

strategies which may not necessarily materialize. For example Figure 4.6-C of the

Transportation Studyshows 11 lanes across Wiehle Ave. VDOT recommends including a

reverse engineering analysis where reasonable transportation facility supply is assumed for 2030

and travel demand, in terms of land development, is desired. Essentially, how much

development can a reasonably assumed transportation network handle?

56. Because of the levels of vehicular traffic congestion anticipated, it is important that the plans

for the TODs include mitigation measures to provide for emergency vehicle access, even during

periods of traffic gridlock. Possible actions included:

a. Using smaller, more maneuverable fire trucks,

b. Identifying clear paths for emergency vehicles under congested conditions,

c. Including staging areas for fire and EMS operations during emergencies,

d. To the extent possible, providing emergency response facilities within or near the study area,

e. Designating helicopter landing areas.

57.TODs are designed to minimize dependence on single-occupant vehicles, and some TOD

proponents see vehicular traffic congestion as a useful incentive for transit and non-motorizedtravel. Accepting LOS F in some locations as proposed could have negative effects on rubber-

tired transit and paratransit modes. Various bus modes, including connector, commuter and bus

rapid transit vehicles, as well as paratransit modes such as vanpools, carpools, taxis, and car

sharing would be hampered by higher levels of congestion. Where possible, the development

plans should include provisions for operation of transit and paratransit vehicles during congested

periods. Intelligent Transportation Systems (ITS) concepts such as Bus Lanes with Intermittent

Priority should be considered in the design of the TODs.

58.Preferential parking pricing for high occupancy vehicles and higher exit tolls on the Toll Road

during congested periods should be considered as a congestion mitigation technique.

59.The queues reported are based on Synchro, in which upstream impacts and gridlock are not

evident. A more accurate picture of the future queues can be found using an average of multipleSimTraffic runs.

60.As new streets are added and existing roadways are improved and widened, access management

standards should be applied.

61. Future detailed analysis and traffic studies for rezoning applications should examine details

such as the addition of turn lanes and turn lane lengths.


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62. Care should be taken with triple lefts and opposing dual lefts as are shown in Figures 4.9A-C

of the Transportation Study. VDOT may agree with the proposed protected left for triple lefts ifand only if the necessary geometry which includes 15 ft wide turn lanes and 5 ft separation

exists. The feasibility of these improvements should be considered knowing the geometric

requirements and which intersections have limited right-of-way availability. Those that do not

have sufficient right-of-way should be modeled as split phasing.

Summary

Due to significant concerns with the cumulative impacts of other development within the region,

deficiencies in the Synchro analyses, and trip making assumptions the VDOT does not believe that

this report contains sufficient information to evaluate the system of new and expanded

transportation facilities and suggests that the report be refined and resubmitted incorporating thecomments within this letter to determine if the transportation facilities will indeed support the

proposed development as required by 24VAC30-155-30.

Furthermore, an inherent inconsistency is introduced in the proposed amendment by introducing a

level of service standard of E, but not proposing mitigation measures to achieve this standard. If

Fairfax County finds it necessary to stipulate a level of service standard the following methods

should be considered: reduced intensity of development, an expanded transportation network, or a

level of service standard of F. As noted in VDOTs Traffic Impact Analysis Regulations

Administrative Guidelines, just identifying future transportation needs is not sufficient.

The lack of any analysis of the DTR, the imbalance between development intensity andtransportation capacity, and the failure to address level of service F situations are all significant

concerns. Without addressing these major items, if all development proposed by the Comprehensive

Plan Amendment be approved and constructed, there may be failing levels of service many hours of

the day with constrained/limited mobility for the movement of goods and people.

Please contact me if you have any questions.

Sincerely,

Paul J. KraucunasPaul J. Kraucunas, P.E.

Land Development Program Manager

Documents

Dulles Corridor Study Vdot Findings 09-16-13